import java.util.Scanner;

public class 小红的字符生成 {
    //https://www.nowcoder.com/practice/f8659377ca104b1aad45dd2fb564c940?tpId=376&tqId=2608571&ru=/exam/oj&qru=/ta/15-days-help/question-ranking&sourceUrl=%2Fexam%2Foj%3FquestionJobId%3D10%26subTabName%3Donline_coding_page
    //贪心 + 位运算
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        StringBuilder sb = new StringBuilder();
        int count = 0;
        while(n != 0){
            if((n & 1) == 1){
                sb.append((char)(count + 'a'));
            }
            count++;
            n = (n >> 1);
        }
        System.out.println(sb.toString());
    }
}
